The invention relates to novel U.V. stabilizers, processes for the preparation of these compounds, and the use of these compounds for stabilizing organic substances sensitive to U.V. radiation, and to products entirely or partly composed of substances thus stabilized.
Of numerous organic substances such as polymers, films, organic coatings, wax-like substances, resins, colorants and cosmetic preparations it is known that they may degrade under the influence of ultraviolet light. This degradation may manifest itself in various ways, such as in the deterioration of mechanical properties and color.
A large group of organic substances which are often exposed for a long time to daylight containing U.V. radiation is formed by both natural and synthetic polymers and by films and organic coatings. From the patent literature numerous compounds are known which may have a stabilizing influence on the degradation of organic substances exposed to ultraviolet light. In this connection mention is made of the Swiss Pat. Nos. 388 253, 396 831 and 396 832. Although the compounds mentioned in them have favorable properties, there is still found to be a great need for compounds which on the one hand can be prepared without difficulty and on the other hand display an even larger molar extinction and a more favorable absorption maximum in the ultraviolet radiation region of the solar spectrum.
It has now been found that said need may be provided for by incorporating in the polymers a stabilizing amount of one or more previously unknown compounds.